Numerous sensors are known in the art for detecting the position or relative movement of an object. The sensors are often exposed to harsh environments and must therefore be capable of reliably operating after long periods of exposure to extreme heat, cold, water, vibration, and/or electromagnetic interference. In addition, the sensors may be located in explosive or highly flammable environments that preclude the use or presence of anything that may produce a spark or other ignition source.
The advent of fiber optics in sensors has allowed for the development of spark-free or combustion-free sensors that are less susceptible to electromagnetic interference. However, the need still exists for a sensor, such as an optical sensor, that can reliably operate for extended periods in harsh environments.